1. Technical Field
The present disclosure relates to gear transmission mechanisms and, more particularly, to a planetary gear transmission mechanism.
2. Description of Related Art
A commonly used planetary gear transmission mechanism generally includes a sun gear, a stationary gear, a plurality of planetary gears, and a planetary bracket connecting the sun gear and the planetary gears. The sun gear, the stationary gear, and the planetary gears are cylindrical gears. The stationary gear forms an inner gear ring. Each planetary gear meshes with both the sun gear and the inner gear ring of the fixing gear, such that each planetary gear can be rotated by the sun gear. Since the inner gear ring is stationary, each planetary gear not only rotates along its rotation axis but also along the rotation axis of the sun gear, thereby moving the planetary bracket. When two or more similar planetary gear transmission mechanisms are cascaded, a two-stage or multi-stage transmission system is achieved. The planetary gears are used to split the power of the planetary gear transmission mechanism, such that the load capacity of the planetary gear transmission mechanism is enhanced. However, the planetary gear transmission mechanism adopting cylindrical gears generally presents considerable radial size, and cannot be used in miniaturized applications, such as a pipeline maintenance robot. In addition, another commonly used planetary gear transmission mechanism adopting bevel gears presents the same axial size issues, plus reduced rigidity, thereby decreasing the stability of transmission.
Therefore, there is room for improvement within the art.